A Few Layup Questions

Discussion in 'Fiberglass and Composite Boat Building' started by CatBuilder, Jan 1, 2011.

  1. CatBuilder

    CatBuilder Previous Member

    The mold came out nicely! Pictures to follow soon.

    I have a couple random questions about laying up my triaxial over the foam.

    First Question

    I have to do long strips, 50" wide, from bow to stern (or stern to bow). The designer insisted, as did a prominent NA from this forum. I'll go with their advice. I have virgin Coercell foam to attach a single layer of 34oz (1150g) triax to.

    Can I work my way along and then just stop in the middle??

    Is there anything preventing me from wetting out half the boat length in one day, then going to sleep and waking up the next day to start where I left off if it is one long, continuous piece of trixial?

    Second Question

    The bilge area is shaped like a long, stretched out bowl. My fabric is, of course, flat. How do people usually drape the fabric so that it doesn't have wrinkles when it's going into the inside of a bowl-shaped mold? Is this an issue, or am I over thinking?
     
  2. gonzo
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    gonzo Senior Member

    If you wait a day, the resin will start curing, harden and produce a huge wrinkle where you stopped. Specifications for using a single strip is so the fibers are continuous. It is possible to make it adhere if you do it in two sections but will require re-engineering if it changes the specs. How long is it that you can't do it in a day? A 70' hull can be easily done in a day from chine to sheer. To stretch the fabric and make it lay evenly use a broom.
     
  3. CatBuilder

    CatBuilder Previous Member

    Ok, that wrinkle makes sense now that I think about it. So the glass would be "less than flat" at the edge where you stopped for the night. In the morning, when you got going, you would have some glass not laying down nicely, making a big wrinkle.

    I guess I was just trying to envision what would happen if things took longer than expected. I guess I just have to press on no matter what. It's only 45' x 50", so maybe it'll go faster than I'm imagining. I was planning to do one 45' x 50" strip each day, sanding the lap joint where I do the next 45' x 50" strip the next day. It doesn't take too many days of this (maybe 3 days max?) to get the layup done.

    I guess I'm overthinking stuff. Thanks for that tip on the broom!
     
  4. gonzo
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    gonzo Senior Member

    A trick to make it faster is to pre wet the fabric. Make a long flat table and cover it with plastic. Lay the fabric and soak it with resin. You can do sections at a time. Roll it on a piece of 2"PVC pipe and keep on wetting. Wet the core and unroll the fabric on it. You will need at least one helper.
     
  5. mark775

    mark775 Guest

    The 45' x 50" roll of wetted out triax might get a tad unruly with that technique.
    I presume, Cat, that you are using slow cure epoxy (I have not read your thread). Don't sweat it. Keep your shop under 60°F or so. Take a break or even lunch if you need to. It is going to go much more smoothly than your trepidations foretell. Mask everything in sight on the mold and under (You do not want to track epoxy/dirt drips or spills around because you may need to enter a clean area while working) - even where you are going to put the next laminate to avoid a drip of partially cured resin under that laminate or bat poop or whatever. It should be like an operation with just the area you are going to lay the laminate showing. Next, peel away the next piece of masking to expose the subsequent target. If epoxy ran onto an area of masking, make sure it didn't run under the tape. The bowl shaped area may not lay down nicely with that heavy fabric untill it is wetted and the fibers can more easily move. It's easy to get pooling there if not careful trying to roll out the shape of the fabric. Try hard to get in place dry first (with your hands). I would consider a cut... No, I wouldn't - I would ask the designer what his feelings are on it. A problem with slow cure is that it is also slow set, so if there is latent tension in the fabric, or a bit of a pool of resin, it may look good when you're done, then bubble,wrinkle or run when you go home and sleep. You have to hang around for hours after you are done to make sure. Only crank the heat when you are sure.
     
  6. hoytedow
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    hoytedow Carbon Based Life Form

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  7. War Whoop
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    War Whoop Senior Member

    How are you planing on dispensing the epoxy on the laminate and do you have a helper??
     
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  8. War Whoop
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    War Whoop Senior Member

    Hoyt thanks.
     
  9. Steve W
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    Steve W Senior Member

    Yes, you will definatly get a wrinkle as Gonzo said if you do it in two hits,also concur re the pre wetting,the good news is that,yes you are overthinking the problem of getting it to lay in, especially if you pre wet it it should just lay in nicely. 34oz is fairly stiff and is not too easy to wet from one side with GP epoxy so it is easier to wet out the plastic on the table and lay the glass in it,then finish the wetout from the top, i find that pouring the resin on and spreading with a squeegee works best and less equipment to cleanup or throw,others prefer a roller. Make sure you weigh the glass and resin and sqeegee out any excess if you have any. I agree with mark to mask off anything you may drip resin on or get dirty. Good luck.
    Steve.
     
  10. Brian2009
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    Brian2009 Junior Member

    I'm building a Woods Design Flica 37 in foam/glass/epoxy. I started this fall and have completed one hull below the "knuckle" so I only have limited experience but thought I might comment.

    My layup is two layers of 18 oz biaxial cloth, then Divinycell, then two more layers of 18 oz biaxial. I'm using a female mold that is 37' long. The outside circumference of my hull requires almost two full 50" wide sheets at its widest point, and obviously much less than that as it tapers down toward the bow/stern.

    The day we started the hull there were four adults including myself. We placed two strips of 50" cloth on two separate layers (for a total of four - 37' strips). Next we precoated contour foam with epoxy, added a thickened layer of epoxy/cabosil mix to the foam, and placed about 80% of the hull foam. I'd guess this took about ten hours from beginning to end and we were all beginners. There were only three of us left for the last five hours.

    Since I had about 20% of the foam work left to do, I finished it over the next few weeks before getting ready to place the inside layers of glass (again, this next layer of glass would require four strips 37 feet long).

    The original glass work for the outer hull skin went incredibly easy; it was pre-coating and applying the foam I found to require more attention. So, I was emboldened to attempt the four sheets of glass on the inner hull skin with just my wife and I in hopes of saving other manpower resources for more challenging and critical times.

    Perhaps I was two bold. We completed glassing the inner hull skin and it probably took maybe six hours? We could work much faster this time because we knew what to expect. But it was a full on rush the entire time. Not because of the epoxy, but because we were working outside and were running out of daylight. If I was to do this much in this amount of time again, I would use three adults.

    If I was to give myself more time, I could do it again with just my wife and I. But - it requires careful advance planning. The key thing is I have all the glass in place before I start. Prior to "epoxy day" I layout the first two strips of glass, which is the first layer, directly in the mold and cut them to fit. I duct tape them to the side of my mold so gravity has them hanging down and in place. Next I layout the other two strips of glass, which is the second layer, and cut them to fit. Then I tape them to the top side of my mold as well.

    Now here is the key - I leave the second layer of glass taped to the mold, but I roll it up and place it on the top side of the mold so that I have a 37' long roll of glass the entire length of my mold on each side of the mold. When I'm ready for it, all I have to do is push it over into the mold and it unrolls into it's previous fitted shape (with a little guidance).

    To wet out the first layer of glass it is already in the mold; so I just pour on the epoxy and roll it in. I prefer to use rollers, but I do use both rollers and squeegees. I use Resin Research epoxy with a 50 minute pot life. I've found there is plenty of time. I've worked front to back, middle out, three people on one side, etc., and it really didn't seem to matter. Whatever works best for you. The point is, I had plenty of time. As long as the current layer of glass is in place before the epoxy starts to kick, there is no worry. Just keep working whichever direction your headed and keep a wet edge. Take your time.

    The second layer of glass is the easiest - I unroll it into the mold, then work I work my way down the glass laying it out flat onto the previous layer. I usually try to do this quite quickly. Then I flip down the other side and do the same. All my glass overlaps on the keel, so I end up eight layers thick.

    If the first layer of glass is wet before I place the second; fine. If it is tacky then that is ok as well. If it is set up that is also ok. So it really doesn't matter that much for the time frame. However, I try to put the second layer on that day so I get a chemical bond.

    Another thing I should say is that my outside working temperature is from about 65-75 Fahrenheit.

    So my end result is four layers of continuous glass, no pleats or cuts, and a chemical bond on the epoxy throughout. When it warms up this spring and I do the second hull I'm thinking about doing everything in one long day - four strips inside, all the foam, then four strips outside. Start in the morning then work till done - I'd use four people. Why? Sanding and preparation between layers is a real pain and waste of time. One big day will make the same progress as several weeks of other days, and it will be a better product.

    So, to answer your question, I'd place the glass you're talking about in one continuous strip in one day. I think you should have plenty of time - and I'm a beginner also.
     
  11. Brian2009
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    Brian2009 Junior Member

    I've attached a single image of what I just tried to describe.
     

    Attached Files:

  12. CatBuilder

    CatBuilder Previous Member

    Let's see if I can answer all the questions first. Actually, first I'd like to thank Mark for that post. Thanks, Mark.

    Epoxy type: System Three Silvertip Laminating Epoxy. It's thin stuff, to help we out the triaxial better. It's also sticky, "gluey" type stuff, apparently. It's supposed to be made for just this type of operation. I have both slow and fast hardener (this stuff only has slow and fast). A description of the epoxy is here:

    http://www.systemthree.com/store/pc/SilverTip-Laminating-Resin-c10.htm

    the epoxy datasheet is here:

    http://www.systemthree.com/reslibrary/tds/Silvertip_C&L_Resin_TDS.pdf

    Seems like good stuff for this because it's designed for this application, has no blush, can be re-coated up to 72 hours without sanding and has a good setup time. Also, it can work in colder temperatures, which FL has right now.

    I don't have any climate control in my shop. My shop is a tent, but I'm well within range for this epoxy (and others) which is why I'm in FL to build.

    Epoxy Dispensing: I planned on wheeling my epoxy around with me, mixing and applying epoxy without a helper. I am not sure if I will be using a thickened (thixotropic) epoxy on the lower layer to help fill things in yet. I will be performing a test to see if I can just use neat epoxy, Corecell and the triax, or if I need to put a thickened epoxy on the CoreCell first. Still waiting for CoreCell, so I'll have those test results as soon as the foam arrives.

    So basically, I was hoping I could wheel my epoxy along with me and mix up little bits of the 5 gallon or so total for this layup as I go, wetting out on the part, soaking it in, squeegeeing off excess, typical hand layup. That's what I hope to do in a day's time.

    I thought it would be easier for one guy to wet out this strip on the part than for me to do it on a table.


    Layup Geometry: I am laying up the first 50" of this mold in the picture, measured from the bilge, or far left hand side of the mold. The 50" runs from the bilge centerline (left edge of mold) to about 1/3 to 1/2 of the way across the mold. All is reachable and all is squeegeeable with relative ease.

    [​IMG]

    Neatness: I will be sure to be as neat as humanly possible. I have some experience from building the wooden hulls I built (that split) and I saw how epoxy can get out of control on you. I also saw how using plastic in the proper spots can help a lot on clean up. I'll be sure not to get any epoxy anywhere I don't want it... and have safeties in place to protect against that.
     
  13. gonzo
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    gonzo Senior Member

    WEST has a laminating resin of lower viscosity that wets very well.
     
  14. AndrewK
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    AndrewK Senior Member

    CatBuilder, you are over estimating the difficulty.
    Higher weight triaxial glass can be very stiff but they will conform to the shape when wet. Some are lot stiffer than others, this is due to the differences in stitching.
    This is why you should get samples before you purchase the boat lot quantity.
    You want to compare how pliable and how easily the cloth is to wet out for starters.
    Secondary features are is there a salvedge edge for overlaps, is the 0 deg tow flat and how big are the gaps between the tow, is the construction -45/0/+45 or the more common -45/+45/0.
    -45/0/+45 is better.

    The 750gsm triax will wet out from the top, dont know about the 1150gsm you have to determine this.

    Your first strip will be from the deck radius to the middle of the hull. Mark the foam 1270mm down from this radius at the highest point of the hull. From this mark make a set of marks from the stem to transom parallel to the waterline, align the edge of your first strip with these marks.
    Cut 15m + the width of the extra backing material that is to go under the mast bulkhead + 200mm extra from your roll of glass.
    The extra material is for this reason, plan to do the entire strip on your own in one hit, you will be able to do this. But if things go wrong the first time the extra material will allow you to stop at the mast b/h as this is the best place to make your overlap. I am guessing it will be approx 600mm wide.
    If this does occur cut your glass to this point early enough so that you do not contaminate the cut off with resin. Peel ply this overlap zone as a minimum, personally I would peel ply the entire laminate.

    Unroll this strip onto the job following the reference marks and trim of the excess along the deck radius, leave approx 25mm spare. To do this best to put a sheet of thin plastic down first as the bare dry foam is very gripy, plastic allows the glass to slide easily.
    If you use a 200 min or so hardener then you will have plenty of time to do this on your own even if temperature is 35'C.
    Weigh your glass and determine the resin required allowing for foam surface wet out.
    Get a bunch of cheap 9L buckets, pre weigh resin portion to make a mix batch of say 5kg into each bucket at the start of the job. This is so that you just add the hardener mix and pour onto the job once you get going.

    The inboard glass edge along the reference line will be horizontal so you will not have drain out so no need for masking providing you peel ply this edge as a minimum.
     

  15. CatBuilder

    CatBuilder Previous Member

    Wow, Scott. Great post as well. Thanks.

    Did I read correctly that you guys lay up the outer skin, stick foam to it, then lay up the inner skin? All at once??! That does give me quite a bit of confidence. :)

    My method differs a little bit in that I place the foam with no outer skin first, then glass just the inside and remove it from the mold, glassing the outside later on. So, this step is just putting a single strip of 50" wide (34oz - 1150g) triaxial down the already placed foam from bow to stern (45'). If you guys could get all that done in one day, even I... as one person, should be able to wet out a 45' piece of triax and call it a day.

    Your post definitely helped me put it in perspective... especially hearing that a beginner was able to make that kind of time.
     
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